Vinegar Herbicide Update

So it's been 10 days since I sprayed the 30% vinegar. Initially I got a good response. Everything turned brown. But I was curious about the long term effects. I've got my answer......

Two classification of my weeds really died back, almost 100%-- certain tender type grasses and all non-grass weeds (excepting honohono, which I will discuss later). To date, these haven't shown signs of growing back. But the mature, aggressive tropical grasses are now sending out new leaves and new shots (kikuyu grass, St. Augustine grass, hilo grass, and bermuda grass). I didn't spray any molasses or california grasses, so I have nothing to report.  I'm not surprised by this. Some tropical grasses are ultra tough. Also of note, all the mosses on the concrete walkway are totally dead. 

No grass regrowth and the tender young honohono grass is dead.
Only the weeds that I failed to spray show any green color.

A couple of people have voiced concern about the vinegar changing the soil pH. I was curious about that too. First keep in mind that I didn't saturate the soil with vinegar. I simply wet the leaf surface. I didn't even spray enough that the vinegar was dripping off the leaves. So today I tested the soil. To date there has been no change in the soil pH. In a way I wasn't surprised. You see, I live downwind from a volcano that has been spewing SO2 for decades, which results in acidic rain. The two of those years most recently, my rain pH has been fluctuating between 4 and 6. Even with this, my soil pH hasn't changed much, most likely due to the constant decomposition of organic material in the soil and the availability of calcium carbonate (via bone and coral sand added to the compost). All those soil microbes and compost help moderate the soil pH.

This area completely browned out, but it's starting
to show some green. 

New grass leaves....a variety that I don't know the name of.
Lots of brown dead leaves in this photo. 

The before photo, where the St Augustine grass
was burned brown by the vinegar. 

The St Augustine grass is growing new shoots. 

The mature tropical grasses survived the initial spraying of 30% vinegar. But I bet that timely repeated spraying would cause the plant to run out of energy and die back. Timeliness is probably the key. In my own situation, I have another weapon.....mulch. After spraying the vinegar, I will be applying a layer of fresh mulch. That will help prevent the grasses from growing back. And any that put up shoots through the mulch will get resprayed and remulched. I think I've hit upon a way to control most of my weeds in the gardens. Now my next experiment will be on that dratted bermuda grass! I have a gut feeling that bermuda grass isn't going to be that easy to vanquish. We shall see. 

Now for honohono. The spray quickly killed the leaves. And the tender non-rooted tips also died. But some, not all, of the mature rooted stems survived. I plan to spray any new growth that I see. And I'm guessing that the honohono grass will be defeated! Again, we shall see.

No regrowth where it was sprayed. 

Vinegar Herbicide

I'm experimenting with vinegar lately. A friend (thanks "J") recently told me that 30% vinegar is now available on Amazon, and they are shipping to Hawaii! Last time I checked, shipping to Hawaii was not available. So I ordered a couple gallons in order to check it out. Would it be effective against our tropical weeds and grasses?

I have many questions pertaining to using vinegar as a herbicide. 

... What strength gives good results against my weeds? 

... Is it effective on a cloudy day, or does full sun give best results? 

... What happens if it rains an hour, two hours, or 3 hours after it is sprayed? 

... How heavily must it be sprayed? 

... Will it noticeably change the soil? 

... How close to a good plant can it be sprayed? 

... If the rain washes the vinegar into the soil, will it damage the good plants? 

... Do I need to add liquid soap as a sticker? 

 There's a few things that I was already aware of. 30% vinegar is strong enough to burn sensitive parts of my body. So care must be taken to avoid splashing it into eyes, mouth, etc. In the past I've worked with pickling vinegar (10%) and it burned the skin around my finger nails, so with this stronger stuff I plan to wear gloves. My tender spots apparently don't like vinegar. 

Moss covered concrete walkway. 

After photo.

It's been raining daily, so I waited for a day where there was a low chance of rain. I finally got one, yahoo!!!! Using a spritzing hand sprayer, I sprayed a few test areas. I sprayed to just wet the plants, but didn't over wet to the point that the vinegar ran into the soil. 

Assorted weeds and grasses

After photo. 

Within hours the sensitive plants started to either bleach out or wilt. Even the honohono grass wilted! By the next day I could easily see where I had sprayed and where I hadn't. By the third day, most of the weeds looked dead or dying, including the grasses. 

Stone steps. Weeds growing in the crevasses. 

After photo.

I'm impressed. So I answered my first question......30% gives good results. I also answer the "how heavily to spray" question....just wet the leaves. I sprayed weeds right up to good plants, protecting the good plant from the direct spray with a piece of cardboard. So far, I haven't seen any herbicide damage signs in the good plants. 

On the third day it rained. So now I'll watch to see what happens when the rain washes the vinegar into the soil. We shall see if the soil pH changes or if the good plants start showing damage. 

I didn't use soap. At 30% strength it doesn't seem to need it. But I'm going to try watering the vinegar down to 15% and see what happens. I may use soap in that solution. 

I plan to try using it on a cloudy day to see if that makes a difference. And if it happens to rain on the day I spray, I'll keep records and see what effect that rain had. 

Bermuda Grass Scourge

Gardeners who have never experienced bermuda grass don't seem to really understand how difficult this grass is to control. It is tenacious to the max. Outside of repeatedly dousing it with herbicides, the only way I've been able to successfully battle it is to pick out the underground stolons every time I turn the soil. It's tedious and takes months, if not years, to eliminate this grass from gardens. And I can never let my guard down because it will creep back from many feet away.

Many folks have suggested smothering it out. I've never had much success with that method because this is what this grass does when covered.....,,.

Metal roof panel, trash cover removed 

What it looked like when I lifted the roof panel. 

Close up look. Amazing how it survived. 

That piece of roofing has been sitting on that spot for well over a year, with various trash piled atop it. Today I removed the debris and heaved the roof panel aside, finding lots of bermuda grass stolons and sun starved leaves still alive underneath. This grass simply doesn't know about quitting. Look carefully and you'll see that nothing else survived. 

Needless to say, I'm taking revenge upon this grass by pulling it out. Yeah, yeah, yeah. It will only creep back, but it feels good eliminating at least this one little patch for a while. I will win my little micro battles when I can. 

Using Weeds

"K" emailed and asked what do I do with the weeds I get from my gardens. Well, it depends upon where they are needed the most. When I weed, I call it "harvesting" because they are a usable asset. They surely don't go out in the trash! 

1- Harvested weeds often go into my pallet grow boxes. When I have time, I'll chop them up first with a lawnmower before dumping them into a box. But when I'm short on time, they will get chucked in whole. Yes....seeds and all. I don't bother taking the time to handpick out the seeds. Most seeds will die when the pile heats up, so it's not a problem. 

2- Another good use is to use them as fill for one of the hugelpits. Again, I'll chop them up before adding if I have the time. Otherwise they go in whole. 

3- Today I had a good pile of weeds, mostly Bermuda grass that the community gardeners removed from an unused garden bed that's being put back into use. 

And also a pile of assorted weeds that have been drying out for a week. Time to grind them up, lawnmower style. 

I used the ground up weeds to apply extra mulch to some young potato plants. These chopped weeds will dry out over the next couple days and thus won't root and be a problem. Occasionally a few of the Bermuda grass stolens survive in the loose mulch, but they are easy to pull out if they start showing any signs of regrowth. 

Most of my gardens are mulched regularly, so weeds are not a serious problem anymore. They only get out of hand in beds that don't get mulched in a timely fashion. Yes, if I don't pay attention to a particular garden bed, the weeds & grass take over, though I'm getting better at keeping ahead of things. 

My main "weed" source now is my pasture areas that I'm upgrading. Plenty of ferns and rough brushy stuff to harvest. But the gardening areas have gradually become less and less weedy. 

The one thing that I no longer use weeds for is making my compost. It's just easier and quicker to use grass clippings. 

The Battle With The Grass Weeds

Here's my main problem.....grass. This tropical grass is nothing like I've dealt with before. Pull it out and it comes back, for real. Lots of tenacious underground runners that are almost impossible to remove in entirety. 

For the past many months I've been getting almost daily rain. Often light, but it's daily and the grasses are thriving on it. Most weeds are easy to remove....yank...gone. But the grass just keeps spreading. 

I've tried both concentrated vinegar spray and a flamer, both with poor results. A thorough dousing with vegetable oil works, but then the soil is saturated in oil, which kills worms and soil microbes. And what happens to the oil? Where does it end up? Sounds bad to me. Several readers suggested strong salt applications, but since I'm getting rain almost every day, the salt would simply leech away without killing the grass. 

Another thing that worked well enough for me in the past was weedwacking the grass right down to soil level. While it didn't kill the blasted stuff, it set it back several months. But not now. Too much rain, so the grass simply bounces right back. 

Thus I've opted to start over again at square one by killing the grass the only way I've found to be effective in this situation. I've opted for a dose of commercial herbicide. 

So why bother getting rid of the grass in the first place? Fear of a disabling fall. The grass gets really slick with repeatative rains. Just walking from the car to the house can become rather hazardous. I'd rather be walking on the compacted base course driveway than the slippery grass. 

Weeds Can Be My Friends

Most gardeners and farmers talk about weeds as though they are an anathema. Once upon a time, I was one of them. I spent lots of hours trying to eliminate every weed. Not any more. I now don't mind if some weeds co-exist in the gardens as long as they don't over proliferate. And I now see weeds as a resource to be utilized. Not that I want my gardens to be so weedy that it deminishes my harvests, but weeds can at times be beneficial. 

Certain weeds can be used as catch crops for pests. I notice that whitefly seems to infest the volunteer nasturtiums before invading the rest of the garden. Thus I can aggressively treat the nasturtiums without jeopardizing my edible crops. 

Some weeds are liked by the rabbits and chickens and make a nice addition to their diet. In fact, I now intentionally grow purslane, elevating it from it's weed status to a fodder crop. 

Most weeds, except the Bermuda grass, can be cut off at the soil level and controlled, acting as mulch. I will pull & drop, or chop & drop, weeds all the time. Why bother carrying them to a compost pile if I don't need the fill? Just leave it where it drops and let it become mulch. 

I use some shade loving plants to grow in areas that I can't use for most vegetables, like in the photo above. They are weeds, but I use them as a resource. They grow where little else will. I harvest their leaves to use as mulch and compost. They grow back without any assistance in my part, so I can re-harvest them again in the future. Pictured above, a type of philodendron grows under the coffee trees. A type of fern also grows there. Eventually they get prolific enough that I can quickly harvest trashcanfuls. 

It doesn't take long to clear under the trees. I used these leaves and stems as fill for a pallet grow box. And even though the ground looked clear after pulling, I know from experience that the plants will grow back again. So you could say that thus area has given me a harvestable crop -- weeds. 

Weeds also help trap fallen leaves that would otherwise be blown away in the tradewinds. In areas without weeds, the ground tends to be bare. With weeds, the ground gets coated in a natural leafy mulch. 

One other thing that I've noticed about allowing weeds to grow and be harvested in my shade areas. The soil there has a much better look to it. I don't know why. But the soil looks better than in shaded areas with no weeds and those shade areas where I don't harvest the weeds. I guess there is something going on with the weed regrowth process and soil health. So totally excluding weeds doesn't seem to help the soil, nor does allowing weeds to totally fill in and maintain a status quo. There is something to the repeative partial clearing. I don't understand the science behind it. 

I've also taken advantage of weeds to help establish my pastures. A friend was eliminating weeds from her landscape gardens, including among them a viney weed that livestock love to eat. The weeds were heavy with seed. So I brought the bags and bags of weeds to my pasture areas, allowed the weeds to dry out, them carried them around the pastures giving them a good shake to scatter the seeds. Many of those seeds are germinating, helping to fill in bare spots in the pastures with edible weeds. The sheep will appreciate it. 

Using Taro to Shade Out Weeds

I've toyed around with using various crops to help shade out "weeds" and improve the soil for future garden plots. Tropical grasses are my number one weed, and they are very hard to eliminate without using a herbacide or else covering the ground in black plastic (or something else durable and solid) for many months. I decline to broadcast spray herbacide and I'd like to come up with a solution that doesn't involve spending lots of money. Giant rolls of black, heavy grade, durable plastic sheeting aren't cheap. I'm cheap, rolls of plastic aren't! 

Since I already have a decent amount of veggie producing beds, I'm not in a real hurry to get more ground into production. So time is on my side. This gives me time for tinkering around with ideas. 

I have some sort of a taro that really likes to grow here. It produces giant leaves when fertilized with manure, thus creates dense shade beneath itself. So I've been using it to help get rid of weeds. 

Above, I measured some of those leaves. Many were close to four foot long! Without lots of manure being used, the leaves are more usual 18"-24". But since I'm looking for complete shade, the manure helps make those jumbo leaves. 

The shade beneath this taro keeps most weeds from thriving. The weeds tend to be spindly and small. About once a month I'll throw some grass clippings between the taro plants to act as a smothering mulch. It works on just about everything but certain grasses. But the grass also gets spindly with weak roots. So it becomes fairly easy to pull out. After several months of grass clipping mulch and hand pulling what grass happens to survive, the area becomes almost weed free. Not quite, but much better than before. 

This particular taro patch is just about ready for converting to a veggie garden. The beauty of this system for me is that I don't have to dive in and plant veggies right away. There's no rush. The taro will still grow for a number of months, giving me time to get my act together. Plus....with all the manure and mulch being used, the soil has had a chance to become fertile and a home to scads of worms. 

This particular taro is quite "itchy". So I don't bother trying to use it for people food. But I will cook it on my outdoor wood burning cook stove for feeding to the chickens and pigs. The corms need 2-3 hours of cooking to make the pigs happy, but the chickens will eat it with much less cooking. The leaves and stems need at least an hour for happy pig food. Since I have a virtually unlimited supply of cooking wood, it doesn't cost me anything to cook it for so long. I wouldn't bother with it if I had to pay for fuel. I would just add it to the compost pile instead. 

Thimbleberry

We have a rather sticky-ly thorny bush here that grows in patches on my homestead place. I've known it as thimbleberry since moving here. Just recently I had a mainland visitor who informed me that the leaf was quite different from the thimbleberry he was familiar with, so I had to go look it up. And he was right! Turns out that his homeland thimbleberry is a kissin' cousin to mine. His has the scientific name Rufus parviflorus while mine is Rufus rosifolius. The leaf shape is the most apparent difference I first noticed. The Hawaiian thimbleberry leaf looks more like a rose bush. 

Right now the thimbleberries are flowering and creating little red berries the size of raspberries. When ripe, they are red. It's easy to know when they are ripe because they readily come right off the bush and look like little red thimbles. While edible, I find there taste to be insipid. (Hey, how often do you get to use that word!) In plainer words, they're flavorless. But if I wanted, I could surely eat them. The fruit production is sparse, so it would take a massive area of thimbleberry to produce enough fruit to make a cup of jam. But a small handful is do-able and would make a nice decorative statement in salad or atop a cake. 

My rabbits like to eat thimbleberry. They'll eat the entire bush except for the thickest stems, and those they will debark. So I allow thimbleberry to grow so as the be part of my rabbits' diet. 

I find thimbleberry to be an annoyance.......except for the rabbit forage part. It's very thorny. It creates a tangle. It spreads readily via underground shoots. It is difficult to remove by hand and grows back if you leave roots behind. 

For rabbit forage I allow it to grow about 2-3 foot high then snip it off at ground level, using a hand pruning shears  and then cut it into 12-18 inch long lengths. 

Weeds the complicated answer

Weedless gardening? 

One of the frequent topics people ask me about is weeds. People seem to be manic about eliminating each and every weed from their gardens. When I tell them that some weeds are ok in my gardens, they tend to drift away, thinking that I'm crazy in some way. So I'd like to address some of the weed phobias gardeners have....

... Eliminate all weeds - bare earth syndrome. I've seen plenty of gardens that look so incredibly neat without a weed to be seen. Just veggie plants and plenty of bare earth. I really don't like seeing bare earth exposed to the sun and drying wind. Soil organisms and worms don't like it either, which in turn causes your veggies to be affected. While I wouldn't advocate a dense weed population, low growing weeds are a better option than bare soil. Especially if the weeds are not the type to adversely affect your veggies. Purslane is a good weed. So is plantain, oxalis, dandelion. Most ground hugging weeds don't bother the veggies much, help protect the soil, help with humidity and pests. Problem weeds for me would be vining things, tall growing things, and most grasses. My veggies don't like those. 

... Mulch to eliminate weeds. That's ok in my book. I'm an advocate of mulch, so if it's a way of being  weedless, I have no issue with it. I use mulches for soil health, with weed control being a side benefit. 

... Weeds bring bugs. Gardeners often notice that certain weeds are associated with bugs, so they are quick to eliminate all weeds. The assumption is that no weeds = no bugs. Wrong. Actually I like certain particular weeds around because they can be good bug indicators. Certain bugs tend to show up first on certain weeds. Example, whitefly. They always seem to show up on my nasturtiums first before the veggies. Thus I leave some nasturtium weeds growing near or in the gardens. 

    Some weeds actually attract "good bugs", those that attack or eat the nasty bugs. I don't have a list of those weeds with me, but you could goggle it. I'm aware that there are predatory wasps that are attracted by milkweed. And flowering weeds, especially dandelion, attract bees. Yes, that's good. Bees are pollinators. And just the opposite of attraction, some weeds repel or deter bad bugs. 

    Certain weeds can be used as trap crops. For example, nasturtiums tend to attract black aphids. When there is a breakout of these aphids, I can opt to spray the aphids with soapy solution to kill them. Same for whitefly. Thus I can protect the garden veggies from a major bug attack. 

... Disease spreaders. I haven't found that to be the case, but I do notice that certain weeds are great disease indicators. I'll sometimes spy things like powdery mildew on some weeds before the veggies, thus giving me a heads-up to watch my veggies closely. Same for rust, another fungal disease. Weeds don't cause these diseases. It's just that they succumbed to them first. 

Not all weeds are welcome in my garden that's for sure. Too many weeds can choke out my veggies, leaving them no space to grow. Tall weeds could block out the sun. Aggressive weeds could hog the soil moisture and nutrients. Vining weeds could cover or bind the veggies. Spiny weeds could make working in the garden painful. So not all weeds are good. But a few weeds here and there don't bother me or send me into a nervous tither. As I've said, some I find useful. 

Useful? Oh yes, some are even edible! Purslane is one that I will leave to grow when I come upon it. And all of them are useful when pulled or wacked then added to the mulch or compost.